Abiotic factors and aging alter the physicochemical characteristics and toxicity of Phosphorus nanomaterials to zebrafish embryos

Effects of biogenic and commercially available iron-oxide nanoparticles on algal and bacterial growth in freshwater and marine water

We investigated the potential toxic effects of iron oxide magnetic nanoparticles (IOMNPs) of varied size, synthesized through biological and chemical methods on freshwater and marine microalgae and bacterial species. The study provides insights into pollution and ecological impacts of NPs. IOMNPs of two sizes, 20-50 nm (quasi-spherical) synthesized using a cell-free fungal extract (biogenic method), and 104 nm (spherical) obtained from a commercial source (chemical method), were tested for aggregation, bioavailability, and toxicity at multiple concentrations (12.5, 25, 50, 100, and 125 µg mL-1). Microalgal growth media (Bold's basal media and sea salt media [SSM]) was used for aggregation analysis of IOMNPs using dynamic light scattering (DLS) technique. DLS analysis showed similar aggregation patterns for both type of IOMNPs, with relatively larger aggregate formation in SSM. Toxicity assessments showed that biogenic IOMNPs of smaller size 20-50 nm were non-toxic, while commercial IOMNPs of large size (104 nm) significantly reduced bacterial cell density and microalgal lipid and carotenoid content at higher concentrations. Further, transmission electron microscopy and X-ray fluorescence analysis confirmed IOMNP uptake by microalgae. TEM images showed more pronounced structural damage caused by the uptake of commercial IOMNPs. Our findings provide crucial insights into the differential impacts of IOMNPs based on their size and synthesis methods on key aquatic microorganisms and their potential to mitigate issues related to NP pollution.

Systematic investigation on the pharmaceutical components and mechanism of the treatment against zebrafish enteritis by Sporisorium reilianum f. sp. reilianum based on histomorphology and pathology

ETHNOPHARMACOLOGICAL RELEVANCE

Sporisorium reilianum f. sp. reilianum (SSR) is a fungus isolated from a medicinal plant. Recorded in the "Compilation of National Chinese Herbal Medicine" and "Compendium of Materia Medica," it was used for preventing and treating intestinal diseases, enhancing immune function, etc. In this study, we investigated the chemical composition and bioactivity of SSR. Network pharmacology is utilized for predictive analysis and targeting pathway studies of anti-inflammatory bowel disease (IBD) mechanisms. Pharmacological activity against enteritis is evaluated using zebrafish (Danio rerio) as model animals.

AIM OF THE STUDY

To reveal the treatment of IBD by SSR used as traditional medicine and food, based on molecular biology identification of SSR firstly, and the pharmaceutical components & its toxicities, biological activity & mechanism of SSR were explored.

MATERIALS AND METHODS

Using chromatography and zebrafish IBD model induced by dextran sulfate sodium (DSS), nine compounds were first identified by nuclear magnetic resonance (NMR). The toxicity of ethanol crude extract and monomers from SSR were evaluated by evaluating the phenotypic characteristics of zebrafish embryos and larvae, histomorphology and pathology of the zebrafish model guided by network pharmacology were conducted.

RESULTS

The zebrafish embryo development did not show toxicity. The molecular docking and enrichment pathway results predicted that metabolites 3 & 4 (N-trans- feruloyl-3-methoxytyramine & N-cis-feruloyl-3-methoxytyramine) and 7 & 8 (4-N- trans-p-coumaroyltyramine & 4-N-cis--p-coumaroyltyramine) have anti-enteritis activities. This paper lays an experimental foundation for developing new drugs and functional foods.

Mechanisms of PVP-functionalized silver nanoparticle toxicity in fish: Intravascular exposure disrupts cardiac pacemaker function and inhibits Na+/K+-ATPase activity in heart, but not gill

Polyvinylpyrrolidone-functionalized silver nanoparticles (nAgPVP) are popular in consumer products for their colloidal stability and antimicrobial activity. Whole lake additions of nAgPVP cause long term, ecosystem-scale changes in fish populations but the mechanisms underlying this effect are unclear. We have previously shown that in fish, nAgPVP impairs cardiac contractility and Na+/K+-ATPase (NKA) activity in vitro, raising the possibility that heart dysfunction could underlie population-level exposure effects. The goal of this study was to determine if nAgPVP influences the control of heart rate (fh), blood pressure, or cardiac NKA activity in vivo. First, a dose-response curve for the effects of 5 nm nAgPVP on contractility was completed on isometrically contracting ventricular muscle preparations from Arctic char (Salvelinus alpinus) and showed that force production was lowest at 500 μg L-1 and maximum pacing frequency increased with nAgPVP concentration. Stroke volume, cardiac output, and power output were maintained in isolated working heart preparations from brook char (Salvelinus fontinalis) exposed to 700 μg L-1 nAgPVP. Both fh and blood pressure were elevated after 24 h in brook char injected with 700 μg kg body mass-1 nAgPVP and fh was insensitive to modulation with blockers of β-adrenergic and muscarinic cholinergic receptors. Na+/K+-ATPase activity was significantly lower in heart, but not gill of nAgPVP injected fish. The results indicate that nAgPVP influences cardiac function in vivo by disrupting regulation of the pacemaker and cardiomyocyte ionoregulation. Impaired fh regulation may prevent fish from appropriately responding to environmental or social stressors and affect their ability to survive.

3D printed porous membrane integrated devices to study the chemoattractant induced behavioural response of aquatic organisms

Biological models with genetic similarities to humans are used for exploratory research to develop behavioral screening tools and understand sensory-motor interactions. Their small, often mm-sized appearance raises challenges in the straightforward quantification of their subtle behavioral responses and calls for new, customisable research tools. 3D printing provides an attractive approach for the manufacture of custom designs at low cost; however, challenges remain in the integration of functional materials like porous membranes. Nanoporous membranes have been integrated with resin exchange using purpose-designed resins by digital light projection 3D printing to yield functionally integrated devices using a simple, economical and semi-automated process. Here, the impact of the layer thickness and layer number on the porous properties - parameters unique for 3D printing - are investigated, showing decreases in mean pore diameter and porosity with increasing layer height and layer number. From the same resin formulation, materials with average pore size between 200 and 600 nm and porosity between 45% and 61% were printed. Membrane-integrated devices were used to study the chemoattractant induced behavioural response of zebrafish embryos and planarians, both demonstrating a predominant behavioral response towards the chemoattractant, spending >85% of experiment time in the attractant side of the observation chamber. The presented 3D printing method can be used for printing custom designed membrane-integrated devices using affordable 3D printers and enable fine-tuning of porous properties through adjustment of layer height and number. This accessible approach is expected to be adopted for applications including behavioural studies, early-stage pre-clinical drug discovery and (environmental) toxicology.